Ditto for upload.html.
Stored db name as 'db' because calls to bulkSave looked stupid.
Stored previous doc versions as uploaded_docs object.

This is written as an object with the _id as key to ease lookup.
Changed upload.html to expand upon existing doc structure.

Fields with re-assigned null/""/"null"/etc. are removed from the new document.
Removed all_or_nothing from bulkSave call.

This option will commit everything at the cost of conflicting documents. I
liked this idea before, but managing bulk conflicts now sounds expensive.
Fixed update of existing document fields.

Half of these are plain stupid coding errors and the other half did not respect
existing fields of the previous document. The priority should always be
new-value > existing-value > undefined.
I realize that it is kind-a difficult to un-set doc.type and doc.time from
within the form (this is probably a good thing).
GeoJSON feature geometries are ignored if a GeoJSON_clone is found either in
the uploaded or previous data. As with the other fields, it can be unset with
an explicit empty column.
The 'revert' button just deletes all the documents right now and is another
story.
Removed exemplary 'time' input value.

Otherwise it writes itself into the documents by accident.